Google Plus Logout按钮无效

Question

我已经关注了谷歌开发者网站https://developers.google.com/+/quickstart/android的快速启动示例应用程序，它在同一活动中的登录按钮，注销和撤销按钮上运行良好。

但是当我尝试将注销按钮移动到新活动并调用注销按钮时，它开始崩溃。

这就是我想要做的事情：

  @Override
  public void onConnected(Bundle connectionHint) {
    // Reaching onConnected means we consider the user signed in.
    Log.i(TAG, "onConnected");

    // Update the user interface to reflect that the user is signed in.


    // Retrieve some profile information to personalize our app for the user.
    Person currentUser = Plus.PeopleApi.getCurrentPerson(mGoogleApiClient);

    mStatus.setText(String.format(
        getResources().getString(R.string.signed_in_as),
        currentUser.getDisplayName()));

    Intent myIntent = new Intent(LoginActivity.this, LogOutActivityty.class);   
    //myIntent.putExtra("GUsername", currentUser.getDisplayName());    
    startActivity(myIntent);

    // Indicate that the sign in process is complete.
    mSignInProgress = STATE_DEFAULT;
  }

这是我的LogOut活动：

 Logout = (Button) findViewById(R.id.sign_out_button);

    Logout.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            if (mGoogleApiClient.isConnected()) {
                Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
                mGoogleApiClient.disconnect();
                mGoogleApiClient.connect();
               Intent i = new Intent(LogOutActivity.this, LoginActivity.class);
               startActivity(i);
               Toast.makeText(getApplicationContext(), "Logged out using Google Account", Toast.LENGTH_LONG).show();
            }

        }
    });